1. Field of the Invention
This invention is related in general to the field of maintenance management systems. In particular, the invention comprises utilizing a set of procedures for addressing maintenance issues.
2. Description of the Prior Art
In many industries, such as strip-mining activities, it is common to use heavy equipment to facilitate acquiring, moving, and placing large and heavy items. In the strip-mining industry, heavy equipment may include dozers, drills, haul trucks, loaders, and shovels.
A dozer is a tracked or wheeled piece of equipment that moves earth with a large blade to clear or level areas. A drill is another tracked piece of equipment utilized to create holes, usually for the placement of explosives, utilizing rotation or percussion. Haul trucks carry waste and ore material between locations at the mine site. Often, these trucks operate in a cycle of loading, hauling, dumping, and returning for the next load. Loaders are rubber-tired pieces of equipment used to move rock and load trucks. Shovels are similar to loaders, however they are usually larger and are tracked vehicles. Shovels are generally either powered by diesel engines or large electric motors.
Strip-mines and similar industrial locations are stressful environments for these heavy pieces of equipment. Some equipment, such as drills, may experience extreme use resulting in severe stress and strain on both static components (frames, superstructure, and undercarriage) and moving parts (engines, motors, gears, shafts, and hoses). The mine can be a very hostile environment for all equipment. There are severe loading issues for all mine equipment. Other equipment, such as haul trucks, may be utilized in a near-constant cycle (load, haul, dump, return) that results in steady and persistent wear in some components and unpredictable wear in other components. Temperatures in these environments may also be extreme and can vary greatly over a period of hours or months. There are numerous reasons that equipment breaks down. Some of the principal reasons include, use of equipment beyond its design, operator abuse, poor design, manufacturer defects, poor or incorrect maintenance, wear-out, accident, etcetera. Dust and dirt can also accumulate on moving parts and result in excessive and premature wear. Impurities, including water, fuel, dust, and dirt, may be inadvertently introduced into lubricating fluids, resulting in additional wear.
This wear on both static and dynamic parts often leads to failure of an equipment component. Failure is characterize by the termination of the ability of the equipment to perform its required function to a set standard. Failure results in downtime, which is calculated as the measurement of time the equipment is unavailable to fulfill its performance requirements divided by its intended utilization period.
Because the cost of heavy equipment is very high, any downtime decreases the return on investment for the associated equipment. The impact of a failure may be higher in hidden costs (i.e. production losses) than the actual repair capital costs of the equipment. An equipment's reliability is measured as a probability that it will perform satisfactory for a given period of time, under specified operating conditions, and its mean time between failure (“MTBF”) is a measure of its uptime (the opposite of downtime) in a given period of time divided by the number of failures in that time period. For these reasons, downtime is carefully tracked and extraordinary measures are employed to prevent or minimize it, as much as possible.
Maintenance activities are performed to ensure equipment performs its intended function, or to repair equipment which has failed. Preventive maintenance entails servicing equipment before it has failed by replacing, overhauling, or remanufacturing components at fixed intervals, regardless of their condition. Periodic maintenance, such as scheduled replacement of components or lubricants, is performed at regular intervals based on either use or time.
Predictive maintenance is a strategy based on measuring the condition of equipment in order to assess whether it will fail during some future period, and then taking appropriate action to either prevent the failure or make allowance for the anticipated equipment downtime. One method of implementing predictive maintenance is termed Oil Analysis, whereby lubricants (including hydraulic fluid and engine oil) are sampled and subjected to a variety of tests. These tests are designed to identify contaminants, such as water, fuel, and dust, and measure lubricant viscosity.
Data from a piece of equipment may be transmitted from the field to the maintenance office or to a service center or off-site original equipment manufacturer (“OEM”) facility for analysis, referred to as remote condition monitoring. Remote condition monitoring may be utilized for failure reporting, or to report the status of the equipment such as time-in-use or lubricant levels. Another method of maintenance planning is to employ trend analysis, whereby predictive maintenance tools analyze the equipment=s operating conditions and estimate the potential wear and failure cycle of the equipment. These preventative and predictive maintenance programs are designed to facilitate the implementation of planned maintenance, whereby maintenance tasks are organized to ensure they are executed to incur the least amount of downtime at the lowest possible cost.
The effectiveness of these maintenance strategies is measured by the mean time between failure (“MTBF”), the equipment uptime divided by the number of failures in a particular period of time. Another measurement tool of maintenance effectiveness is the mean time to repair (“MTTR”). However, the MTTR can be influenced by additional factors, such as failure response time, spare parts availability, training, location, and weather. Once a failure has occurred, failure analysis may be performed to determine the root cause of the failure, develop improvements, and eliminate or reduce the occurrence of future failures.
Maintenance tasks are generally managed through the use of work orders, documents including information such as description of work, priority of work, job procedure, and parts, material, tools, and equipment necessary to complete either a preventative maintenance or repair task. Work order requests are proposals to open work orders and submitted to persons authorized to generate work orders.
Once a failure has occurred, or is eminent, a piece of equipment may generate an alarm or an indication that the equipment is being utilized outside its operating profile. Alarms and indications may be generated by on-board sensors, OEM monitoring systems, or trend analysis. Additionally, equipment operators and maintenance technicians may initiate an alarm or notification during an operational pre-inspection or based on equipment performance. If an operator does not have the authority to issue an alarm or notification, the condition may be communicated to a maintenance analyst, who, in turn, generates an alarm or notification.
The problem with the current state of alarm handling is that alarms are not handled in an organized manner or, in many cases, not at all. Alarms may not be discovered until failure because there is no formal process for handling the alarms, and if there is a process for reviewing this information they are typically ineffective because of the large number of alarm events. After problem identification, there are often several different procedures in place to handle them. The response to an alarm will often include different people who apply their own methods for handling it. This leads to an inconsistency in how the alarm is handled and a corresponding degradation in the efficiency and effectiveness of the alarm handling process. Therefore, it is desirable to provide a consistent, effective, and efficient method for handling alarms, indications, and notifications which can be tracked, measured, and improved upon.